Method of repairing cylindrical workpieces and lathe therefor

Abstract

A method of repairing a drill pipe having first and second connector ends, each of the first and second connectors ends including a threaded portion and sealing portions, with a lathe having a chuck with longitudinally spaced first and second sets of jaws, the method comprising the steps of mounting the drill pipe in a lathe, gripping the first connector end of the drill pipe with each of the first and second sets of jaws, orienting the first connector end by manipulation of the first and second sets of jaws into a working position; and rotating the drilling pipe against a working tool to machine the threaded portion and sealing portion of the first connector end and produce a new threaded portion and sealing portion of the first connector end. A lathe with longitudinally spaced first and second sets of jaws is also disclosed. A device for positioning of subsequent workpieces without repeating alignment steps is also disclosed.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:  
     
       1. A lathe for machining a drill pipe, the lathe comprising: 
       a lathe motor defining a longitudinal axis and having a first side and second side, the second side spaced longitudinally from the first side along the longitudinal axis;  
       a chuck mounted on the first side of the lathe motor;  
       first and second sets of jaws adjustably mounted on the chuck, the first set of jaws being mounted radially in the chuck at a first longitudinal position and the second set of jaws being mounted radially in the chuck at a second longitudinal position spaced from the first longitudinal position, each of the first and second sets of jaws including x and y positioning jaws;  
       a steady rest located on the second side of the lathe motor to receive an end of a cylindrical workpiece; and  
       the motor operably connected to the chuck for rotating the chuck.  
     
     
       2. The lathe of claim  1  in which each set of jaws includes first and second pairs of jaws mounted orthogonally to each other. 
     
     
       3. The lathe of claim  1  in which the first set of jaws is mounted further away from the motor than the second set of jaws, and the jaws of the first set of jaws are longer in a direction perpendicular to the first set of jaws than the jaws of the second set of jaws.